Interesting... Your gateway's provider is Suddenlink (22.214.171.124), which appears to be randomly inserting a 1 second delay... which is not really terrible.
What troubles me is when you open up the wait time to 15 seconds, you have a consistent 10 second delay added between your terminal the satellite, which might indicate some kind of handshaking protocol issue. It's always the second number, not the initial one though... and that's weird.
Are you on Linux natively or running through a VM?